def fcntl(fd, op, arg=0):

    return 0

# coding=utf-8

def ioctl(fd, op, arg=0, mutable_flag=True):

    if mutable_flag:

        return 0

    else:

        return ""



def flock(fd, op):

    return



def lockf(fd, operation, length=0, start=0, whence=0):

    return